Human LAG-3 Antibody

Catalog #: MAB23195 Datasheet / COA / SDS

Catalog #	Availability	Size / Price	Qty
MAB23195-100
MAB23195-SP

Detection of Human LAG‑3 by Western Blot.

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Summary Data Examples Preparation and Storage Reconstitution Calculator Background Product Datasheets Related Research Areas

Human LAG-3 Antibody Summary

Species Reactivity

Human

Specificity

Detects human LAG-3 in direct ELISAs.

Source

Monoclonal Mouse IgG_2A Clone # 1009611

Purification

Protein A or G purified from hybridoma culture supernatant

Immunogen

Mouse myeloma cell line NS0-derived recombinant human LAG-3
Leu23-Leu450
Accession # P18627

Formulation

Lyophilized from a 0.2 μm filtered solution in PBS with Trehalose. *Small pack size (SP) is supplied either lyophilized or as a 0.2 µm filtered solution in PBS.

Label

Unconjugated

Applications

Recommended Concentration

Sample

Western Blot

2 µg/mL

See below

Flow Cytometry

0.25 µg/10⁶ cells

See below

CyTOF-ready

Ready to be labeled using established conjugation methods. No BSA or other carrier proteins that could interfere with conjugation.

Please Note: Optimal dilutions should be determined by each laboratory for each application. General Protocols are available in the Technical Information section on our website.

Scientific Data

Western Blot

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Detection of Human LAG‑3 by Western Blot. Western blot shows lysates of HEK293T human embryonic kidney cell line either mock transfected or transfected with human LAG-3. PVDF membrane was probed with 2 µg/mL of Mouse Anti-Human LAG-3 Monoclonal Antibody (Catalog # MAB23195) followed by HRP-conjugated Anti-Mouse IgG Secondary Antibody (Catalog # HAF018). A specific band was detected for LAG-3 at approximately 100 kDa (as indicated). This experiment was conducted under reducing conditions and using Immunoblot Buffer Group 1.

Flow Cytometry

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Detection of LAG-3 in Human PBMCs by Flow Cytometry. Human peripheral blood mononuclear cells (PBMCs) were either untreated (bottom panel) or treated with with 5 µg/mL PHA (top panel) for 5 days. PBMCs were stained with Mouse Anti-Human LAG-3 Monoclonal Antibody (Catalog # MAB23195) followed by Allophycocyanin-conjugated Anti-Mouse IgG Secondary Antibody (Catalog # F0101B) and Mouse Anti-Human CD3 epsilon PE-conjugated Monoclonal Antibody (Catalog # FAB100P). Quadrant markers were set based on isotype control antibody staining (Catalog # MAB003) (data not shown). View our protocol for Staining Membrane-associated Proteins.

Reconstitution Calculator

Preparation and Storage

Reconstitution

Reconstitute at 0.5 mg/mL in sterile PBS.

Shipping

Lyophilized product is shipped at ambient temperature. Liquid small pack size (-SP) is shipped with polar packs. Upon receipt, store immediately at the temperature recommended below.

Stability & Storage

Use a manual defrost freezer and avoid repeated freeze-thaw cycles.

12 months from date of receipt, -20 to -70 °C as supplied.
1 month, 2 to 8 °C under sterile conditions after reconstitution.
6 months, -20 to -70 °C under sterile conditions after reconstitution.

Background: LAG-3

LAG-3 (Lymphocyte activation gene-3), also known as CD223, is a member of the immunoglobulin superfamily (IgSF). The mature LAG-3 protein is a 496 amino acid (aa) membrane protein with a 421 aa extracellular region which contains four IgSF domains, a 21 aa transmembrane region and a 54 aa cytoplasmic region. LAG-3 and CD4 molecules share < 20% aa sequence homology but have a similar structure (1, 2). Both molecules bind to MHC class II. LAG-3 binds to MHC class II with higher affinity compared to CD4. Both LAG-3 and CD4 genes are located on the distal part of the short arm of chromosome 12.

LAG-3 is an activation-induced molecule, expressed on activated T cells and NK cells, but not on resting T cells. Studies using LAG-3 ^-/-mice have shown significant delay of T cell apoptosis following antigen stimulation and increased size of memory T cells pool following infection (3, 4). It also has been reported that anti-LAG-3 antibodies up-regulate T cell activation by blocking interaction of LAG-3 and MHC class II. The study has demonstrated that LAG-3 is selectively expressed on activated CD4⁺CD25⁺ T_Reg cells and plays a role in their suppressive activity (5). This evidence indicated, unlike the interaction of CD4 with MHC class II that plays a positive role in T cell activation, LAG-3 binds to MHC class II and negatively regulates T cell activation through LAG-3 signaling. On the other hand, studies have shown that binding of LAG-3 to MHC class II molecules on antigen presenting cells induce maturation of dendritic cells and cytokine secretion by monocytes through MHC class II signal transduction (6). Taken together, LAG-3 may have two major functions, it negatively regulates T cells activation through LAG-3 signaling and stimulates antigen presenting cells which express MHC class II.

References

Triebel, F. et al. (1990) J. Exp. Med. 171:1393.
Baixeras, E. et al. (1992) J. Exp. Med 176:327.
Workman, C.J. and D.A. Vignali (2003) Eur. J. Immunol. 33:970.
Workman, C.J. et al. (2004) J. Immunol. 172:5450.
Huang, C.T. et al. (2004) Immunity 21:503.
Andreae, S. et al. (2003) Blood 102:2130.

Long Name

Lymphocyte-activation Gene 3

Entrez Gene IDs

3902 (Human); 16768 (Mouse); 297596 (Rat); 102122272 (Cynomolgus Monkey)

Alternate Names

CD223 antigen; CD223; LAG3; LAG-3; lymphocyte activating 3; lymphocyte activation gene 3 protein; lymphocyte-activation gene 3; Secreted lymphocyte activation gene 3 protein; sLAG-3